Implement most of qv_scope_create().

The only missing parts are the following:
* Adding hint support
* Adding the Fortran interface

Signed-off-by: Samuel K. Gutierrez <samuel@lanl.gov>

src/quo-vadis.cc

@@ -280,6 +280,7 @@ qv_scope_split_at(
     return rc;
 }
 
+// TODO(skg) Add Fortran interface.
 int
 qv_scope_create(
     qv_context_t *ctx,
@@ -295,7 +296,7 @@ qv_scope_create(
 
     qv_scope_t *isubscope = nullptr;
     int rc = qvi_scope_create(
-        scope, type, nobjs, hint, subscope
+        scope, type, nobjs, hint, &isubscope
     );
     if (rc != QV_SUCCESS) {
         qvi_scope_free(&isubscope);

src/qvi-group-mpi.cc

@@ -57,6 +57,33 @@ qvi_group_mpi_s::barrier(void)
     return qvi_mpi_group_barrier(mpi_group);
 }
 
+int
+qvi_group_mpi_s::self(
+    qvi_group_t **child
+) {
+    int rc = QV_SUCCESS;
+
+    qvi_group_mpi_t *ichild = qvi_new qvi_group_mpi_t();
+    if (!ichild) {
+        rc = QV_ERR_OOR;
+        goto out;
+    }
+    // Initialize the child with the parent's MPI instance.
+    rc = ichild->initialize(mpi);
+    if (rc != QV_SUCCESS) goto out;
+    // Create the underlying group using MPI_COMM_SELF.
+    rc = qvi_mpi_group_create_from_mpi_comm(
+        mpi, MPI_COMM_SELF, &ichild->mpi_group
+    );
+out:
+    if (rc != QV_SUCCESS) {
+        delete ichild;
+        ichild = nullptr;
+    }
+    *child = ichild;
+    return rc;
+}
+
 int
 qvi_group_mpi_s::split(
     int color,

src/qvi-group-mpi.h

@@ -39,6 +39,14 @@ struct qvi_group_mpi_s : public qvi_group_s {
     virtual int size(void);
     /** Group barrier. */
     virtual int barrier(void);
+    /**
+     * Creates a new self group with a single member: the caller.
+     * Returns the appropriate newly created child group to the caller.
+     */
+    virtual int
+    self(
+        qvi_group_s **child
+    );
     /**
      * Creates new groups by splitting this group based on color, key.
      * Returns the appropriate newly created child group to the caller.

src/qvi-group-process.cc

@@ -55,13 +55,9 @@ qvi_group_process_s::barrier(void)
 }
 
 int
-qvi_group_process_s::split(
-    int,
-    int,
+qvi_group_process_s::self(
     qvi_group_t **child
 ) {
-    // NOTE: The concept of coloring with a provided
-    // key doesn't apply here, so ignore.
     int rc = QV_SUCCESS;
 
     qvi_group_process_t *ichild = qvi_new qvi_group_process_t();
@@ -86,6 +82,19 @@ qvi_group_process_s::split(
     return rc;
 }
 
+int
+qvi_group_process_s::split(
+    int,
+    int,
+    qvi_group_t **child
+) {
+    // NOTE: The concept of coloring with a provided key doesn't apply here, so
+    // ignore.  Also, because this is in the context of a process, the concept
+    // of splitting doesn't really apply here, so just create another process
+    // group, self will suffice.
+    return self(child);
+}
+
 int
 qvi_group_process_s::gather(
     qvi_bbuff_t *txbuff,

src/qvi-group-process.h

@@ -39,6 +39,14 @@ struct qvi_group_process_s : public qvi_group_s {
     virtual int size(void);
     /** Group barrier. */
     virtual int barrier(void);
+    /**
+     * Creates a new self group with a single member: the caller.
+     * Returns the appropriate newly created child group to the caller.
+     */
+    virtual int
+    self(
+        qvi_group_s **child
+    );
     /**
      * Creates new groups by splitting this group based on color, key.
      * Returns the appropriate newly created child group to the caller.

src/qvi-group.h

@@ -34,6 +34,14 @@ struct qvi_group_s {
     virtual int size(void) = 0;
     /** Group barrier. */
     virtual int barrier(void) = 0;
+    /**
+     * Creates a new self group with a single member: the caller.
+     * Returns the appropriate newly created child group to the caller.
+     */
+    virtual int
+    self(
+        qvi_group_s **child
+    ) = 0;
     /**
      * Creates new groups by splitting this group based on color, key.
      * Returns the appropriate newly created child group to the caller.

src/qvi-scope.cc

@@ -44,7 +44,7 @@ qvi_scope_new(
 
     qv_scope_t *iscope = qvi_new qv_scope_t();
     if (!scope) rc = QV_ERR_OOR;
-    // hwpool and group will be initialized in qvi_scope_init().
+    // hwpool and group will be initialized in scope_init().
     if (rc != QV_SUCCESS) qvi_scope_free(&iscope);
     *scope = iscope;
     return rc;
@@ -718,29 +718,30 @@ qvi_scope_split_at(
 
 int
 qvi_scope_create(
-    qv_scope_t *scope,
+    qv_scope_t *parent,
     qv_hw_obj_type_t type,
     int nobjs,
     qv_scope_create_hint_t hint,
-    qv_scope_t **subscope
+    qv_scope_t **child
 ) {
     // TODO(skg) Implement use of hints.
     QVI_UNUSED(hint);
 
-    qv_scope_t *isubscope = nullptr;
-    hwloc_bitmap_t cpuset = nullptr;
+    qvi_group_t *group = nullptr;
     qvi_hwpool_t *hwpool = nullptr;
-
+    qv_scope_t *ichild = nullptr;
+    hwloc_bitmap_t cpuset = nullptr;
+    // TODO(skg) We need to acquire these resources.
     int rc = qvi_rmi_get_cpuset_for_nobjs(
-        scope->rmi,
-        qvi_hwpool_cpuset_get(scope->hwpool),
+        parent->rmi,
+        qvi_hwpool_cpuset_get(parent->hwpool),
         type, nobjs, &cpuset
     );
     if (rc != QV_SUCCESS) {
         goto out;
     }
-    // Now that we have the desired cpuset, create
-    // a corresponding hardware and subscope.
+    // Now that we have the desired cpuset,
+    // create a corresponding hardware pool.
     rc = qvi_hwpool_new(&hwpool);
     if (rc != QV_SUCCESS) {
         goto out;
@@ -750,13 +751,20 @@ qvi_scope_create(
     if (rc != QV_SUCCESS) {
         goto out;
     }
+    // Create underlying group. Notice the use of self here.
+    rc = parent->group->self(&group);
+    // Create and initialize the new scope.
+    rc = qvi_scope_new(&ichild);
+    if (rc != QV_SUCCESS) goto out;
+
+    rc = scope_init(ichild, parent->rmi, group, hwpool);
 out:
+    qvi_hwloc_bitmap_free(&cpuset);
     if (rc != QV_SUCCESS) {
-        qvi_hwloc_bitmap_free(&cpuset);
         qvi_hwpool_free(&hwpool);
-        qvi_scope_free(&isubscope);
+        qvi_scope_free(&ichild);
     }
-    *subscope = isubscope;
+    *child = ichild;
     return rc;
 }
 

src/qvi-scope.h

@@ -119,11 +119,11 @@ qvi_scope_split_at(
  */
 int
 qvi_scope_create(
-    qv_scope_t *scope,
+    qv_scope_t *parent,
     qv_hw_obj_type_t type,
     int nobjs,
     qv_scope_create_hint_t hint,
-    qv_scope_t **subscope
+    qv_scope_t **child
 );
 
 /**

tests/test-mpi-scopes.c

@@ -223,6 +223,38 @@ main(
 
     scope_report(ctx, wrank, sub_scope, "sub_scope");
 
+    if (wrank == 0) {
+        qv_scope_t *create_scope;
+        rc = qv_scope_create(
+            ctx, sub_scope, QV_HW_OBJ_CORE, 1, 0, &create_scope
+        );
+        if (rc != QV_SUCCESS) {
+            ers = "qv_scope_create() failed";
+            panic("%s (rc=%s)", ers, qv_strerr(rc));
+        }
+
+        int n_core;
+        rc = qv_scope_nobjs(
+            ctx,
+            create_scope,
+            QV_HW_OBJ_CORE,
+            &n_core
+        );
+        if (rc != QV_SUCCESS) {
+            ers = "qv_scope_nobjs() failed";
+            panic("%s (rc=%s)", ers, qv_strerr(rc));
+        }
+        printf("[%d] Number of cores in create_scope is %d\n", wrank, n_core);
+
+        scope_report(ctx, wrank, create_scope, "create_scope");
+
+        rc = qv_scope_free(ctx, create_scope);
+        if (rc != QV_SUCCESS) {
+            ers = "qv_scope_free() failed";
+            panic("%s (rc=%s)", ers, qv_strerr(rc));
+        }
+    }
+
     char *binds;
     rc = qv_bind_string(ctx, QV_BIND_STRING_AS_LIST, &binds);
     if (rc != QV_SUCCESS) {